This invention relates generally to improvements in the construction of shutters for windows, doors, and the like. More particularly, this invention relates to an improved shutter construction having movable louvers pivotally supported by relatively low friction bushing assemblies and wherein the louvers are shaped to interlock in a closed position to substantially block passage of light and air through the shutter.
In general, shutters for use in selectively blocking or admitting light and air through windows, doors, and the like are well known. Such shutters typically comprise a generally rectangular open frame which supports a plurality of generally parallel louvers mounted for pivoting movement together to an open position and a closed position in response to operation of a tilt rod. More particularly, the louvers are carried by the frame for pivoting movement to the open position with the louvers oriented generally perpendicular to the plane of the frame thereby defining open passages between the louvers for admission of light and air. The louvers can be pivoted together for movement to the closed position oriented generally within the plane of the frame with adjacent louver margins slightly overlapping one another to substantially block passage of light and air through the shutter frame.
In recent years, it has become highly desirable to provide insulated coverings for windows or the like wherein such coverings are designed for substantially complete blockage of light and or air for energy savings purposes while also providing a suitably decorative appearance. More particularly, in a cold temperature climate, it is highly desirable to block cold air currents in the vicinity of a window thereby permitting a substantial reduction in the energy required to maintain the room at a comfortable temperature. Similarly, in a warm climate particularly such as desert areas, it is highly desirable to prevent solar radiation and heated air currents which may pass through or be present in the vicinity of a window from entering a temperature controlled cooled space. Such blockage of radiation and air currents thereby results in a substantial reduction in the required energy usage for maintaining the room at a comfortable temperature.
In general, however, shutters have not provided the desired degree of light and air current blockage for use as an energy savings device. As a result, shutters have generally not been used in many applications in favor of conventional thermal draperies and the like which, although requiring considerably more frequent replacement than shutters, have generally provided a more effective heat transfer barrier. The comparatively poorer performance of shutters is attributable largely to the inability of the movable louvers to provide substantially complete blockage of light and air when said louvers are in the closed position.
Accordingly, one important object of the present invention is to provide an improved shutter construction which substantially completely blocks light and air when the louvers are in the closed position whereby the shutter of the present invention provides a highly efficient energy savings device which meets or substantially exceeds the heat transfer barrier capacity of conventional thermal draperies and the like.
In the past, another drawback to the use of shutters has related to the manner in which the louvers are supported for pivoting movement with respect to the shutter frame. More particularly, the shutter louvers have been conventionally mounted to the shutter frame by unitary dowel pins of wood or the like which have been formed integrally with the louvers or have comprised separate pin structures received into aligned preformed holes in the louvers and the shutter frame. Such dowel pin structures, however, have inherently provided a relatively high friction pivot joint which is subject to binding and frequently results in relatively noisy shutter operation. Moreover, the use of a high friction pivot joint places a limitation on the number of louvers which can be operated without difficulty thereby placing a corresponding limitation on the overall size of the shutter.
Alternative pivot joint structures have been proposed wherein the dowel pins are formed from relatively low friction materials such as nylon plastic or the like. Such plastic pins advantageously reduce friction of the pivot joint compared with conventional wooden dowel pins, but pivot friction is not sufficiently reduced to prevent binding or noisy operation, particularly with shutters having a large number of louvers. Accordingly, another important object of the present invention is to provide an improved relatively low friction structure for pivotally mounting and supporting louvers with respect to a shutter frame.